18.3 Built-in services

The inetd program provides several “trivial” services
internally by use of routines within itself. All these services can
operate both in ‘stream’ and in ‘dgram’ mode. They are:

echo

Send back to the originating source any data received from it. This
is a debugging and measurement tool.

discard

Silently throw away any data received.

chargen

This is a character generator service. It can be operated as both
stream or dgram service. When operating in ‘stream’ mode, once a
connection is established a stream of data is sent out the connection
(and any data received is thrown away). This continues until the
calling user terminates the connection. When operating in
‘dgram’ mode, inetd listens for UDP datagrams, and for
each received datagram, answers with a datagram containing a random
number (between 0 and 512) of characters. Any data in the received
datagram are ignored.

daytime

Send back the current date and time in a human readable form. Any
input is discarded.

time

Send back the current date and time as a 32-bit integer number,
nrepresenting the number of seconds since midnight, January 1, 1900.